I bought a second X1 carbon 1st gen, a model with and I7 CPU, touch and....windows 10 Pro.
My question, is it possible to downgrade it to win 7, I bought the recovery DVD's for the X1 carbon.
Also the X1 becomes very very hot when doing the windows updates...my other X1C with its I5 CPU gets warm too but not so extreme like the X1C touch with its I7 CPU.

Do you have a W7 or a W8 mobo?
If W7, then the BIOS has Slic2.1 and you can use USB or external CD to install the recovery. Activates itself.
If W8, you can use USB or external CD to install the recovery, but you also need the key from a Lenovo W7 COA to activate.

Hmmm, it has a Win8 key embedded in BIOS according to the seller and a Win 10 Pro license sticker on the back but no Win7...
Its been doing updates trough the night , now stuck at 22% and it does not seem to have the intention of continuing.

Right, today I experienced more and more problems with the Win 10 machine...file explorer stopped, unable to restart- had to shut down and restart manually - and sleep mode failed. Last week I lost my audio and had to reset the thing, then another day it refused to charge the battery and again a reset solved the problem but today the reset would only partially solve the file explorer problem but failed to solve the sleep and reboot problems.
So I took the plunge and installed the recovery image I made from my Win7 machine...ByeBye Win10...NEVER again Win10. Its now the second machine where I dumped Win10 after encountering problems.
After 237 updates I am now running Win 7 Pro on my X1C touch...happy days!

Good to hear it's all working again!
And a warm welcome to the club of W10-Loathers!
Time for a glass of of that great Gewürztraminer from Riquewihr, Gueberschwihr or Eguisheim!
(been there more than 50 times in the past!)

Never tried the Gewürztraminer, been several times to Riquewihr...may have to ask for it!

Anyway, the X1C touch is running fine, the only remark I have is that this one is much slower to charge than the other non touch X1C which came out of the box with Win 7...I already noticed this while running Win 10 that it charged much slower and now that I have installed Win 7 on this machine it has remained the same. Could it be a BIOS setting or am I missing the rapid charge software?
Looking at it, as the time passes the battery % remains the same while charging but the remaining time to fully charge increases instead of decreasing!?

Replaced the battery with one which came out off the win 7 machine and I struggled to get it charging...long story short turns out this X1C touch does no longer "accept" a 90 Watt charger (tried 2x different ones) but prefers the 65 Watt charger. With the 90 Watt charger I get erratic and intermitted charging but the same charger works like a charm on the other X1C non touch...now with a 65 Watt brick and this battery it charges normally and counts down the time correctly. Placed the "old battery" back and the same behaviour is noted as the % goes up the remaining time goes up also...So it's a battery and charger problem. The good battery has only 13 cycles and is down to 71% remaining capacity while the faulty has 247 cycles and around 81% capacity.
Looks like I will be shopping for a new battery soon

I am still struggling with the charging issues on the X1 Carbon touch and now that the screen has failed after I dropped the other X1C I am now forced to use the X1C touch as my daily driver.
Fitted the latter with the battery from the broken one - it had the best battery but with this battery I have the same charging issues. It does not get past the 97% and the remaining time increases to full charge instead of decreasing.
Sometimes it refuses to charge and I have to reset the laptop to get it charging again...
This one has been downgraded from W10 after it crashed and I have successfully installed a fresh Win7 on it.
Where is the command for the charging "behaviour" stored, is it in the BOIS?
It seems that only a certain combination of battery model with the software on this machine will allow it to charge correctly...
It has crossed my mind to swap out the mainboards between the 2 but I feel/suspect that they are incompatible between touch and non touch displays...

Ok, update. The other non touch X1C has been repaired, replaced the display and swapped the keyboard as it had an intermitted bad contact in the "enter" key.
Now back to my second X1C, the one with the touchscreen, the ex win 10 machine.
Back with the original battery, charging goes normally up to 99%, 100% seems impossible. From time to time I plug it in to recharge and get the msg "plugged in but not recharging". A restart cures the problem.
Annoying as I keep my laptop normally in sleep modus.
Also I need to unplug the charger during the restart, otherwise I have the problem straight after a restart.
Anybody any idea for a possible solution?
The other X1C can get charged when shutdown or while running without a problem, the other I have to handle with silk gloves to get the battery charged. It has nothing to do with the chargers as it behave exactly the same with different chargers.
The battery's from the other X1C gives amongst this other problems I already reported in the beginning of the topic...